The so-called "Additional Material" tracks have never officially been sanctioned by Lucasfilm Ltd. and are in fact poorly engineered tracks cobbled together from a mixture of tracks from both the Star Wars Trilogy: The Original Soundtrack Anthology and various releases of the Return of the Jedi soundtrack.
Yes, I got that much (as it was on the page I linked to). "The Force Suite" has bits of McNeely's Shadows of the Empire, and "A Star Wars Experience" has MECO and other recordings mixed in--all very amateur.
But "An Ewok Celebration" includes the full album Victory Celebration with a rather nicely done fadeout (if it is indeed amateur). I was just wondering if anyone else had come across it.